As the 5-membered aromatic heterocyclic compound, the following compounds have been reported.    (1) As an adenosine A1 receptor antagonist, a compound represented by the formula:
     wherein A is an aromatic ring; X, Y and Z are each a carbon, a nitrogen, an oxygen or a sulfur; R1 is an optionally substituted aryl or an optionally substituted heteroaryl; R2, R3 and R4 are the same or different and each is a hydrogen, a lower alkyl, a lower alkenyl, a lower alkynyl and the like; R5 and R6 are the same or different and each is a hydrogen or a lower alkyl; B is an oxygen or a sulfur; R7 and R8 are the same or different and each is a hydrogen, a lower alkyl, a lower alkoxy, an optionally substituted aryl, an optionally substituted arylalkyl, an optionally substituted heteroaryl, an optionally substituted heteroarylalkyl, an optionally protected carboxyalkyl and the like has been reported (see EP-A-630894).    (2) As an antihyperlipidemic agent and anti-arteriosclerosis agent, a compound represented by the formula:
     wherein R1 is a C1-6 alkyl; R2 and R5 are each independently a hydrogen, a C1-4 alkyl, a C1-4 alkoxy (except t-butoxy), a trifluoromethyl, a fluoro, a chloro, a phenyl, a phenoxy or a benzyloxy; R3 and R6 are each independently a hydrogen, a C1-3 alkyl, a C1-3 alkoxy, a trifluoromethyl, a fluoro, a chloro, a phenoxy or a benzyloxy; R4 and R7 are each independently a hydrogen, a C1-3 alkyl, a C1-2 alkoxy, a fluoro or a chloro;    X is —(CH2)m- or —(CH2)qCH═CH(CH2)q- (m is 0, 1, 2 or 3, each q is 0, or one is 0 and the other is 1); and    Z is —CH(OH)—CH2—C(OH)R10—CH2—COOH(R10 is a hydrogen or a C1-3 alkyl);provided that each of ring A and B may have only one selected c; from trifluoromethyl, phenoxy and benzyloxy, and —X-Z is present at the 4- or 5-position of a pyrazole ring, and the ortho-position relative to R1 has been reported (see WO86/00307).    (3) As a neurotrophin production or secretion promoter, a compound represented by the formula:
     wherein R1 is a halogen atom, an optionally substituted heterocyclic group, an optionally substituted hydroxy group, an optionally substituted thiol group or an optionally substituted amino group, A is an optionally substituted acyl group, an optionally substituted heterocyclic group, an optionally substituted hydroxy group or an optionally esterified or amidated carboxyl group, B is an optionally substituted aromatic group, X is an oxygen atom, a sulfur atom or an optionally substituted nitrogen atom, and Y is a divalent hydrocarbon group or a heterocyclic group has been reported (see WO01/14372).    (4) As a retinoid-related receptor function regulator, a compound represented by the formula
     wherein R1 is an optionally substituted aromatic hydrocarbon group or an optionally substituted aromatic heterocyclic group;    R2 is a hydrogen or an optionally substituted hydrocarbon group;    X is O, S or a group represented by —NR4— wherein R4 is a hydrogen or an optionally substituted alkyl group; A is an optionally substituted aromatic hydrocarbon group or an optionally substituted aromatic heterocyclic group; R3 is a group represented by the formula: —OR5— wherein R5 is a hydrogen or an optionally substituted hydrocarbon group or —NR6R7 wherein R6 and R7 are the same or different and each is a hydrogen or an optionally substituted hydrocarbon group, or R6 and R7 may form a ring together with the adjacent nitrogen atom has been reported (see WO00/01679).